The most usual method of securing the shell propulsion mechanism of sporting rifles to their supports is that based on inserting screws, normally in an oblique fashion, passING through the said support to be finally screwed into the exterior wall of the said shell propulsion mechanism, with their heads visible from the external face of the support which, together with its oblique layout makes these project somewhat and produce a quite anti-aesthetic effect, in addition to being potentially dangerous to the rifle user, with injury to his hands when they rub against the heads of the said screws.
Spanish Patent application No. 200002464, which issued as Spanish Patent No. 2,194,564, from the same applicant, proposes an articulation device for a shell propulsion mechanism in a compressed air rifle or pistol with a tilting shell propulsion mechanism. The said application describes a system to secure the device to the but body similar to that of the previous paragraph, by means of a series of pass-through holes, preferably located in a radial orientation, in symmetrical angular positions with respect to a longitudinal vertical plane of the rifle or pistol, through which securing screws are inserted that are screwed into nuts. This same patent application does not describe any system to hide these screws from sight.